One layer of .5 should be plenty. I use 2 layers of 2 oz on Star 45’s which are 13lbs, not 2.
okay, I tried 2 layers of .75 ounce cloth, and the hull ripped very easily as I was trying to seperate it from the mold. I’m using a male plug, wrapped with packing tape, waxed, and then pva is applied. Help!
Epoxy (what type) or polyester resin ?
polyester
Sorry - I guess I can’t answer that one, as I use WEST Epoxy, similar plastic tape, but NO wax or PVA. Because epoxy stays a bit flexible after it is able to be handled, I insert a popsicle stick/tongue depressor between glass and tape and a couple of “bursts” from air compressor around the gunwales and at bow and stern it usually loosens the glass for removal. Air volume is less than 20 lbs.
Since it is hard to tell how (and where) the hull “ripped” it is possible the resin got between the tape if not carefully overlaid, or there may have been oil from hands where wax didn’t stick to plastic. I’ve done quite a few hulls and have stayed with 4 oz. cloth, but 1.5 total oz. “shouldn’t” have been easily ripped.
I have laid up around 15 fiberglass BlueSplash hulls now, and there was some experimenting on what weight glass to use. In my case, I am working from a mold that has been waxed before every layup. I used 5-6 wax coats on the first couple of hulls, then dropped back to two layers per hull. No PVA is needed.
Back to the glass. For a very light hull, and probably as fragile as you dare go, I use a layer of 1.4oz S glass backed by a layer of 3.7.oz S glass. The resin is West Systems 105 resin with 206 hardener. The hull weighs less than 50g (2 oz). My first hull is a couple of years old and is holding up fine - no soft spots. For a bit more durable hull, I use two layers of 3.7oz. cloth. The hull is noticeably more rigid, and it ends up weighing about 75g - still pretty light. My experiment with a 1.4oz. layer backed by a 2.0oz layer was a failure. The FG hull was simply too soft to use.
I hope this helps